1. Field of the Invention
This invention relates to methods for selectively occluding blood vessels which supply neoplastic tissue, including tumors.
2. Description of the Related Art
The polyunsaturated fatty acids (PUFAs) are fatty acids having at least two carbon-to-carbon double bonds in a hydrophobic hydrocarbon chain which typically includes X-Y carbon atoms and terminates in a carboxylic acid group. The PUFAs are classified in accordance with a short hand nomenclature which designates the number of carbon atoms present (chain length), the number of double bonds in the chain and the position of double bonds nearest to the terminal methyl group. The notation xe2x80x9ca:bxe2x80x9d is used to denote the chain length and number of double bonds, and the notation xe2x80x9cn-xxe2x80x9d is used to describe the position of the double bond nearest to the methyl group. There are 4 independent families of PUFAs, depending on the parent fatty acid from which they are synthesized. They are:
(1) The xe2x80x9cn-3xe2x80x9d series derived from alpha-linolenic acid (ALA, 18:3, n-3).
(2) The xe2x80x9cn-6xe2x80x9d series derived from linoleic acid (LA, 18:2, n-6).
(3) The xe2x80x9cn-9xe2x80x9d series derived from oleic acid (OA, 18:1, n-9).
(4) The xe2x80x9cn-7xe2x80x9d series derived from palmitoleic acid (PA, 16:1, n-7).
The parent fatty acids of the n-3 and n-6 series can not be synthesized by the mammals, and hence they are often referred to as xe2x80x9cessential fatty acidsxe2x80x9d (EFAs). Because these compounds are necessary for normal health but cannot be synthesized by the human body, they must be obtained through the diet.
It is believed that both LA and ALA are metabolized by the same set of enzymes. LA is converted to gamma-linolenic acid (GLA, 18:3, n-6) by the action of the enzyme delta-6-desaturase (d-6-d), and GLA is elongated to form di-homo-GLA (DGLA, 20:3, n-6), the precursor of the 1 series of prostaglandins. The reaction catalyzed by d-6-d is the rate limiting step in the metabolism of EFAs. DGLA can also be converted to arachidonic acid (AA, 20:4, n-6)) by the action of the enzyme delta-5-desaturase (d-5-d). AA forms the precursor of 2 series of prostaglandins, thromboxanes and the 4 series leukotrienes. ALA is converted to eicosapentaenoic acid (EPA, 20:5, n-3) by d-6-d and d-5-d. EPA forms the precursor of the 3 series of prostaglandins and the 5 series of leukotrienes. Conjugated linoleic acid (CLA; 18:2) is a group of isomers (mainly 9-cis, 11-trans and 10-trans, 12-cis) of linoleic acid. CLA is the product of rumen fermentation and can be found in the milk and muscle of ruminants (see, e.g., Brodie et al. (1999), J. Nutr. 129:602-6; Visonneau et al. (1997), Anticancer Res. 17:969-73. LA, GLA, DGLA, AA, ALA, EPA, docosahexaenoic acid (DHA, 22:6, n-3) and CLA are all PUFAs, but only LA and ALA are EFAs.
Under some well defined culture conditions GLA, AA, EPA and DHA showed a marked differential cytotoxic effect against tumor cells with little or no significant action on normal cells (Leary et al. (1987), S. Afr. Med. J. 62:681-683; Begin et al, (1985), Prostaglandins Leukot. Med. 19:177-186; Das (1999), Nutrition 15:239-241; Das (1991), Cancer Lett. 56:235-243; Das (1990), Nutrition 6:429-434; Seigel et al. (1987), J. Natl. Cancer Inst. 78:271-277; Sangeetha and Das (1992), Cancer Lett. 63:189-198; Begin et al. (1986), J. Natl. Cancer Inst. 77:1053-1062; Das (1992), Asia Pacific J. Pharmacol. 7:305-327). In mixed culture experiments, in which both normal and tumor cells were grown together, GLA showed more selective tumoricidal action compared to AA and EPA (Begin et al. (1986), Prog. Lipid Res. 25:573-576). In addition, direct intra-tumoral administration of GLA can regress human gliomas without significant side-effects (Naidu et al. (1992), Prostaglandins Leukot. Essen. Fatty Acids 45:181-184; Das et al. (1995), Cancer Lett. 94:147-155).
Thus, it is known in the art that certain polyunsaturated fatty acids (PUFAs) have cytotoxic properties towards tumor cells in vitro, and that PUFAs provide the substrates for the generation of lipid peroxidation products which have an inhibitory action on cell proliferation. In addition, tumor cells are known to have low d-6-d activity, which is necessary for the desaturation of LA and ALA to their respective products. Moreover, it has been shown that hepatocarcinogens, diethylnitrosamine (DEN) and 2-acetylamino-fluorine (2-AAF), can suppress the activity of d-6-d and d-5-d resulting in low levels of GLA and AA, EPA and DHA in the tumor cells.
In one aspect, the present invention provides methods of selectively interrupting the blood supply to a neoplastic region, such as a tumor region, causing necrosis of the neoplastic tissue without substantial necrosis of adjoining tissues. The invention also provides methods of selectively causing anti-angiogenic action in a neoplastic region, such as a tumor region, with the result that new blood vessels and collaterals are not formed to sustain the neoplasia.
In particular, the invention provides methods for selectively reducing blood supply to at least a portion of a neoplastic region, in which (a) a proximal artery which carries blood to at least a portion of said region is located and (b) a therapeutically effective amount of a solution of at least one PUFA is intra-arterially injected into the artery, thereby selectively reducing the blood supply in a period of less than one hour or in a period less than ten minutes. In preferred embodiments, the amount of the solution is sufficient to cause occlusion of the artery in a period of less than one minute. In preferred embodiments, the therapeutically effective amount is between 0.5 mg and 50 gm, most preferably between 250 mg and 5 gm.
In some embodiments of the invention, in addition to the PUFA, a lymphographic agent is intra-arterially injected to visualize the proximal artery and blood supply to the neoplastic region. The lymphographic agent may be combined with the PUFA solution and they may be injected together. The progress of the lymphographic agent through the proximal artery and neoplastic region can be observed to determine when the blood supply is effectively reduced and when injection of the PUFA solution can be stopped. In some embodiments, the lymphographic agent is covalently conjugated to the PUFA.
In some embodiments, the PUFA is an EFA. In certain preferred embodiments, the EFA is selected from linoleic acid, gamma-linolenic acid, arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, di-homo-gamma-linolenic acid, alpha-linolenic acid, linoleic acid, and conjugated linoleic acid.
In preferred embodiments, the PUFA is administered in the form of free acid or a salt, such as a lithium salt, a sodium salt, magnesium salt, a manganese salt, an iron salt, a copper salt or an iodide salt. In some preferred embodiments, the PUFA is in the form of a fatty acid derivative, such as a glyceride, ester, ether, amide, or phospholipid, or an alkylated, alkoxylated, halogenated, sulfonated, or phosphorylated form of the fatty acid.
In some embodiments of the inventions, the neoplastic tissue is a tumor. In particular, the neoplastic tissue may be a glioma, hepatoma, lung cancer, colon cancer, breast cancer, ovarian cancer, kidney cancer, skin cancer, Kaposi""s sarcoma, esophageal cancer, stomach cancer, leukemia, or lymphoma. In other embodiments, the neoplastic tissue may result from a non-cancerous cell proliferative disorder.
In some embodiments of the invention, in addition to the PUFA, a therapeutically effective amount of a compound selected from tumor necrosis factor, anti-cancer drugs, lymphokines, and specific polyclonal or monoclonal antibodies is intra-arterially injected. In preferred embodiments, the lymphokine is alpha interferon or gamma interferon.
In some embodiments, the PUFA is covalently conjugated with a pharmaceutical agent chosen from TNF, alpha-interferon, gamma-interferon, an antibody, vincristine, adriamycin, doxorubicin, cyclophospham-ide, cis-platinum, L-asparaginase, procarbazine, camnptothecin, taxol or busulfan.
In another aspect, the invention provides pharmaceutical compositions of a PUFA, or salt of PUFA, in combination with a lymphographic agent or anti-neoplastic agent.
The patent, scientific and medical publications referred to herein establish knowledge that was available to those of ordinary skill in the art at the time the invention was made. The entire disclosures of the issued U.S. patents, published and pending patent applications, and other references cited herein are hereby incorporated by reference.
In order to more clearly and concisely describe the subject matter which is the invention, the following definitions are provided for certain terms which are used in the specification and appended claims.
As used herein, the term xe2x80x9cneoplasticxe2x80x9d means characterized by abnormal tissue that shows partial or complete lack of structural organization and functional coordination with normal tissue, and usually forms a distinct mass which may be either benign or malignant. As used herein, xe2x80x9cneoplasticxe2x80x9d tissue need not exhibit cellular proliferation that is more rapid than normal tissue (e.g., a tumor which has ceased to grow or which is in remission). Neoplastic tissue need not be cancerous (e.g., uterine fibroids, adenomatous polyps of the intestines, adenomas in the lungs or other organs).
As used herein, a xe2x80x9cneoplastic regionxe2x80x9d means an essentially contiguous region of tissue containing neoplastic tissue. A neoplastic region is the smallest volume of tissue that includes the contiguous neoplastic tissue, but may also include normal tissue. Contiguous neoplastic tissues are neoplastic tissues separated by distances of less than one centimeter, and do not include distant metastases (which define separate neoplastic regions). Although not all neoplastic regions are tumors, the terms xe2x80x9cneoplastic regionxe2x80x9d and xe2x80x9ctumorxe2x80x9d will often be used interchangeably herein, and the term xe2x80x9ctumor-feeding vesselxe2x80x9d should be understood to include an artery feeding any type of neoplastic region.
As used herein, the term xe2x80x9cpolyunsaturated fatty acidxe2x80x9d and the abbreviation xe2x80x9cPUFAxe2x80x9d mean any acid derived from fats by hydrolysis, or any long-chain (at least 12 carbons) organic acid, having at least two carbon-to-carbon double bonds. Examples of PUFAs include but are not limited to linoleic acid, linolenic acid and arachidonic acid.
As used herein, the term xe2x80x9cPUFA saltxe2x80x9d means an ionic association, in solid or in solution, of a anionic form of a PUFA with a cation of a small organic group (e.g., ammonium) or a small inorganic group (e.g., an alkali metal). Preferred salts are those between a PUFA and an alkali metal (e.g., lithium, sodium, potassium), an alkali earth metal (e.g., magnesium, calcium) or a multivalent transition metal (e.g., manganese, iron, copper, aluminum, zinc, chromium, cobalt, nickel).
As used herein the term xe2x80x9clymphographic agentxe2x80x9d means any of the class of compounds which are used, or may be used, to visualize lymphatics and lymph nodes, as well as veins and arteries, following an intravenous or intra-arterial injection. Lymphographic agents are typically vegetable oils (e.g., poppy seed oil) which are iodized (e.g., approximately 30-45% by weight), and which may be further derivatized (e.g., ethyl esterification). Examples include the iodized fatty acids of poppy seed oil (commercially available as LIPIODOL ULTRA FLUIDE(copyright) from Laboratoire Guerbet, Paris., France), the ethiodized fatty acids of poppy seed oil (commercially available as ETHIODOL(copyright) from Savage Laboratories, Melville, N.Y.) and iophendylate (PANTOPAQUE(copyright) from Kodak). See, Hom et al. (1957), J. Am. Pharm. Assoc. Sci. Ed. 46:254; Paxton et al. (1975), Brit. Med. J. 1:120. As used herein, the term xe2x80x9clymphographic agentxe2x80x9d means any agent which is useful for non-invasively visualizing blood vessels including, without limitation, radiography, CAT scans, MRI scans, ultrasound imaging, and the like.
As used herein, the term xe2x80x9cangiogramxe2x80x9d means any method of noninvasively visualizing a blood vessel or lymphatic including, without limitation, radiography, CAT scans, MRI scans, ultrasound imaging, and the like.
As used herein, the term xe2x80x9cproximalxe2x80x9d is a relative term which describes the location of an artery with respect to a neoplastic region and a site of intra-arterial injection of a PUFA salt of the invention. An artery is proximal to a neoplastic region if it is upstream of the neoplastic region with respect to blood flow and downstream (or distal) of the site of injection with respect to blood flow. A proximal artery should also be physically close to the neoplastic region such that a substantial portion (e.g., at least 10%, preferably 25%, most preferably greater than 50%) of the volume of a solution injected into the artery would normally pass into arteries, arterioles and capillary beds within the neoplastic region.
The present invention is dependent, in part, upon the discovery of the novel and highly beneficial action of PUFAs, and especially certain PUFA salts, to induce the selective occlusion of blood vessels feeding neoplastic regions, including tumors. This effect is particularly observed when the PUFA is administered in combination with a lymphographic agent comprising iodized fatty acids.
Without being bound to any particular theory of the invention, it is believed that the selective occlusion of the tumor-feeding vessels is not due to embolism or other forms of physical blockage. This conclusion follows from observations in several patients that normal blood vessels, which were sometimes smaller in diameter than tumor-feeding vessels, which were located proximal to the tumor-feeding vessels, and which were closer to the tip of the catheter and the site of injection, were not occluded. If the occlusion were due to embolization, all blood vessels, especially those that were smaller in diameter compared to the tumor-feeding vessels, would be expected to be occluded first. Because the site of injection of the PUFA, as determined by angiographic imaging of the tip of the catheter in several patients, was slightly upstream from the origin of the main tumor-feeding vessels, it is evident that the occlusion of the tumor-feeding vessels is not due to direct injection of the PUFA only into those vessels. Rather, the ability of PUFA to selectively occlude the tumor-feeding vessels but not normal arterial vessels was seen in several patients.
Moreover, in several other patients, a PUFA was injected into normal arteries including the celiac, subclavian and popliteal arteries. During the course of these procedures, no spasms or occlusions (even temporary) of these blood vessels were observed. On the other hand, the PUFA occluded all types of tumor-feeding vessels, irrespective of their size, almost instantaneously. Without being bound to any particular theory of the invention, this rapid action of the PUFA suggests that an intense vasospasm was induced (directly or indirectly) in the tumor-feeding vessels but not in the normal blood vessels and that, following such a vasospasm, thrombosis may have led to permanent occlusion of the blood vessel.
Finally, without being bound to any particular theory of the invention, it is believed that there is an interaction between the PUFA and lymphographic agents of the invention which may account for the effectiveness of the treatment. Thus, lymphographic agents comprising iodized fatty acids, and particularly the iodized fatty acids of vegetable oils, are believed to synergistically interact with the PUFAs to produce a therapeutic effect which is qualitatively different than the effect of either the PUFA or the lymphographic agent alone.
There are several advantages of PUFA treatments of the invention. As shown below, a single injection (or at most two or three injections at separate times, if the neoplastic region is large) is adequate to produce almost permanent occlusion of the tumor-feeding vessels. The PUFAs and their salts are non-antigenic, are known to be relatively safe in the dosages employed, and are stable. The dosage of PUFA needed to occlude the tumor-feeding vessels in a given patient is self-evident during administration: As the PUFA solution is being injected, and as the tumor-feeding vessels are being occluded, resistance to further injection will be felt, at which point the injection can be stopped.
The invention in one aspect provides methods of inhibiting blood supply to a neoplastic region, comprising the steps of (a) locating an artery which carries major blood supply to the neoplastic region and which is proximal to the neoplastic region; and (b) intra-arterially injecting into the located artery a solution of at least one PUFA chosen from LA, GLA, DGLA, AA, ALA, EPA, DHA and CLA. In preferred embodiments, the PUFA is administered in combination with a lymphographic agent.
The invention in another aspect provides methods for treating neoplasias and for facilitating the visualization of remission of a neoplasia which is responsive to treatment, comprising the steps of (a) locating an artery proximal to the neoplastic region which carries a major portion of blood supply to the neoplastic region and which is adjacent to the neoplastic region; (b) obtaining an initial radiographic image of the region; (c) injecting into the artery a mixture of (i) a lymphographic agent, and (ii) a solution of at least one PUFA chosen from LA, GLA, DGLA, AA, ALA, EPA, DHA and CLA; and (d) obtaining second and, optionally, subsequent radiographic images of the neoplastic region after predetermined lapses of time; and comparing the initial radiographic images with the second and/or subsequent radiographic images to assess the extent of remission of the neoplasia.
The invention in another aspect provides methods of causing necrosis in a neoplastic region (e.g., a cancerous tumor) by inhibiting blood supply to the neoplastic region, comprising the steps of (a) locating an artery proximal to the neoplastic region which carries major blood supply to the neoplastic region; (b) injecting into the located artery a mixture of (i) a lymphographic agent, and (ii) a solution of at least one PUFA chosen from LA,GLA, DGLA, AA, ALA, EPA, DHA and CLA; (c) waiting for a predetermined time period and assessing a degree of necrosis in the neoplastic region; and (d) repeating the treatment if necessary to increase the necrosis.
In yet another aspect, the invention provides methods of treating mammalian cell proliferative disorders using a solution of a PUFA, or combinations of PUFAs, administered intra-arterially. The methods are as described above with respect to neoplastic regions.
In each of the foregoing embodiments, the PUFA is preferably in the form of a salt, most preferably in the form of a lithium salt, and is preferably administered in combination with a lymphographic agent. The lymphographic agent is preferably an iodized fatty acid derived from a vegetable oil.
Although the invention is described primarily as it relates to humans, it is envisaged that the methods of the invention are equally applicable to other mammals, including large domesticated mammals (e.g., race horses, breeding cattle) and smaller domesticated animals (e.g., house pets).
The present invention employs PUFAs, preferably in the form of salts, to selectively occlude arteries which provide blood supply to regions of neoplastic tissue. Preferred PUFAs include, but are not limited to, GLA, AA, DHA, EPA, DGLA, ALA, LA and CLA. Other preferred PUFAs include derivatives of the aforementioned PUFAs, including glycerides, esters, ethers, amides, or phospholipids, or alkylated, alkoxylated, halogenated, sulfonated, or phosphorylated forms of the fatty acid. In most preferred embodiments, the PUFA is GLA, AA or DHA.
The PUFA is preferably administered in the form of a salt solution. Suitable salts include salts of a PUFA with a cation of a small organic group (e.g., ammonium) or a small inorganic group (e.g., an alkali metal or alkali earth metal). Preferred referred salts are those between a PUFA and an alkali metal (e.g., lithium, sodium, potassium), an alkali earth metal (e.g., magnesium, calcium) or a multivalent metal (e.g., manganese, iron, copper, aluminum, zinc, chromium, cobalt, nickel). Most preferred are salts of lithium, sodium, magnesium, manganese, iron, copper, and iodides. Combinations of salts may also be employed.
When the PUFAs or PUFA salts are administered in combination with an oily lymphographic agent or other agents, the solution may be formed into an emulsion.
In order to visualize lymphatic vessels, lymph nodes, arteries and veins, lymphographic agents are frequently employed. In the context of the present invention, these agents may aid in both the placement of a syringe or catheter in a proximal artery for intra-arterial injection of a PUFA solution, and may also aid in the visualization of the resulting selective occlusion of tumor-feeding vessels. In addition, such agents may be used in follow-up angiograms to determine whether occlusion has been successful or complete, and to determine whether additional treatments may be necessary. Finally, it is believed that such agents have a synergistic or potentiating effect in combination with the PUFA solutions of the invention, and thereby serve as additional or ancillary active ingredients in the treatments of the invention.
The lymphographic agents can be any of the class of compounds, recognized by those of skill in the art of diagnostic imaging, which are used, or which may be used, to visualize lymphatics and lymph nodes, as well as veins and arteries, by radiography following an intra-lumenal injection. Lymphographic agents are typically vegetable oils (e.g., poppy seed oil) which are iodized (e.g., approximately 30-45% by weight), and which may be further derivatized (e.g., ethyl esterification). Examples include the iodized fatty acids of poppy seed oil (commercially available as LIPIODOL ULTRA FLUIDE(copyright) from Laboratoire Guerbet, Paris, France), the ethiodized fatty acids of poppy seed oil (commercially available as ETHIODOL(copyright) from Savage Laboratories, Melville, N.Y.) and iophendylate (PANTOPAQUE(copyright) from Kodak). See, Hom et al. (1957), J. Am. Pharm. Assoc. Sci. Ed. 46:254; Paxton et al. (1975), Brit. Med. J. 1:120.
The lymphographic agents of the invention may be mixed with the PUFA solutions described above, either to form a new solution or to form an emulsion, or they may be chemically conjugated to the PUFAs of the invention via standard chemistries. Preferably the lymphographic agent is an iodized lymphographic oil, such as an iodized poppy seed oil. Preferably the PUFA solution is mixed with such a lymphographic agent in a ratio of at least about 2:1, or about 1:1, or about 1:1.5, or about 1:2, or about 1:3 (volume/volume). Most preferably the ratio is between 1:1.5 and 1:3 (volume/volume). The preferred lymphographic agent is LIPIODOL ULTRA FLUIDE(copyright) (Laboratoire Guerbet, Paris, France). This lymphographic agent may be safely administered to a typical patient in an amount of about 10 mL/m2, but the attending physician should consider all relevant medical factors in determining the appropriate dosage for any specific patient.
Thus, in another aspect, the invention provides pharmaceutical compositions comprising a PUFA, or a PUFA salt, and a lymphographic agent in solution, or in an emulsion. The PUFA and lymphographic agent may be separate chemical moieties combined in the solution or emulsion, or they may be covalently conjugated. The preferred lymphographic agents and ratios for such a product are as disclosed above. Preferably the final concentration of the PUFA in such a product is at least 5%, preferably at least 20%, and most preferably about 25-50%.
The PUFA solutions of the present invention are preferably administered intra-arterially to an artery which is proximal to the neoplastic region to be treated. The approximate location of the neoplastic region must first be identified by any of the methods known in the art. For example, X-rays, Computerized Axial Tomography (CAT) scans, Magnetic Resonance Imaging (MRI) scans, palpation or direct visual inspection may be used to identify a neoplastic region. Such methods may optionally employ contrast agents, including lymphographic agents or agents specifically targeted to neoplastic tissues (e.g., radioisotope-labeled antibodies against tumor-associated antigens). Once the neoplastic region is identified, an artery which feeds the region (i.e., which is upstream with respect to blood flow to the region) is identified. The intra-arterial injection site is preferably chosen to be close or proximal to the neoplastic region to increase the portion of the dosage which reaches that region, but is also preferably chosen sufficiently far upstream from that region such that all or most of the neoplastic region receives a portion of the injected dosage.
Thus, as one progresses along an artery which feeds a neoplastic region, the artery will branch into smaller and smaller arteries and finally arterioles. At some distant point upstream from the neoplastic region, the artery will feed not only the neoplastic region but also large regions of normal tissue. As the chosen injection site is moved along the artery toward the neoplastic region, the percentage of blood carried by the artery which feeds normal tissue will decrease. By proceeding along the artery toward the neoplastic region, therefore, one can increase the portion of the dosage which reaches the neoplastic region. However, as the injection site proceeds along the artery toward the neoplastic region, one may also bypass branches of the artery which feed the neoplastic region and, therefore, fail to cause occlusion of arteries supplying a part of the neoplastic region. One of ordinary skill in the art may balance these considerations, as well as other considerations (e.g., accessibility of an artery for catheterization), in choosing a site for injection. Thus, the term xe2x80x9cproximalxe2x80x9d is a relative term which describes the location of an artery with respect to a neoplastic region and a site of intra-arterial injection of a PUFA of the invention. Preferably, a proximal artery should also be physically close to the neoplastic region such that a substantial portion (e.g., at least 10%, preferably 25%, and most preferably greater than 50%) of the volume of a solution injected into the artery would normally pass into arteries, arterioles and capillary beds within the neoplastic region. Thus, the hepatic artery might be considered proximal to a neoplastic region in the liver, but the descending aorta would not.
In order to administer a PUFA solution to a proximal artery, the artery is identified as described above, the site of injection is chosen, and the PUFA solution is administered by injection through a syringe or catheter as appropriate to the location. As necessary, the syringe or catheter may be guided to the site of injection by radiological guidance (e.g., X-rays), CAT guidance, MRI guidance, endoscopic guidance, or stereotaxic guidance. In the case of a catheter, the catheter can be inserted into the body at a site quite distant from the proximal artery, and then be guided to the proximal artery. For example, the femoral, brachial and carotid arteries may provide convenient entry points for a catheter which is then routed to a proximal artery elsewhere in the body. In addition, contrast agents may be added to the injected solution to aid in placement of the syringe or catheter, or to aid in visualization of the occlusion of the tumor-feeding vessels.
Appropriate dosages of the PUFA solutions of the invention will depend primarily on the diameter of the proximal artery at the site of injection and the number and size of the arteries and/or arterioles branching therefrom. Preferred dosages range from approximately 0.5 mg for the smallest proximal arteries to 50 gm for very large proximal arteries feeding large neoplastic regions. More typically, dosages of approximately 250 mg to 5 gm are preferred and, as shown in the examples below, dosages of 500 mg to 750 mg are effective for several different types of tumors. However, in most preferred embodiments of the methods of the invention, the PUFA solution is administered in combination with a lymphographic agent, the administration is observed by angiogram, and administration continues until the tumor-feeding vessels are at least partially occluded as indicated by the angiogram. Alternatively or additionally, administration may be continued until a significant increase in resistance to the injection develops, indicating the tumor-feeding vessels distal to the site of injection have been at least partially occluded.
The PUFA solutions of the invention may be administered alone, or in combination with other pharmaceutical agents known in the art for the treatment of neoplasias. Thus, for example, the PUFA solutions may be co-administered with known anti-cancer drugs, including vincristine, adriamycin, doxorubicin, cyclophosphamide, cis-platinum, L-asparaginase, procarbazine, camptothecin, taxol and busulfan. Alternatively, the PUFA solutions may be co-administered with known lymphokines such as tumor necrosis factor (TNF) and/or an interferon (e.g., alpha interferon or gamma interferon) or specific polyclonal or monoclonal antibodies.
Administration of these agents in combination with a PUFA solution, or a PUFA and lymphographic agent solution, may also show a synergistic or potentiating effect.
Thus, in another aspect, the invention provides pharmaceutical compositions comprising a PUFA, or a PUFA salt, and a pharmaceutical agent known in the art for the treatment of neoplasias, either in solution, or in an emulsion. The PUFA and other pharmaceutical agent may be separate chemical moieties combined in the solution or emulsion, or they may be covalently conjugated. The preferred pharmaceutical agents are as disclosed above. Preferably the final concentration of the PUFA in such a product is at least 5%, preferably at least 15%, and most preferably at least 25%. The product may contain substantially more PUFA, up to 100% without any significant side-effects.